Trialkylsulfonium salts of N-phosphonomethyl-glycine and their use as plant growth regulators and herbicides

ABSTRACT

Novel trialkylsulfonium salts of N-phosphonomethylglycine are disclosed herein, having the formula ##STR1## in which R represents C 1  -C 3  alkyl and n is zero or one. The compounds are useful in regulating the natural growth or development of plants and as herbicides.

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation-in-part of application Ser. No. 212,921, filedDec. 4, 1980 now U.S. Pat. No. 4,315,765.

BACKGROUND OF THE INVENTION

This invention is directed to novel chemical compounds and their use inregulating the natural growth or development of plants. In particular,this invention relates to the chemical treatment of plants to altertheir natural growth or development for the purpose of enhancing variousagricultural or horticultural features of the plants, and also to thecontrol of undesirable vegetation.

It is well known among those skilled in the art of agriculture andhorticulture that various features of plant growth can be modified orregulated to produce a variety of beneficial effects.

For instance, certain types of treatment can produce defoliation of aplant in a beneficial manner, i.e., inhibiting further leaf growth whilepermitting further development of the productive plant parts. As aresult, the productive parts demonstrate extra growth, and subsequentharvesting operations are facilitated. Defoliants are particularlyuseful in flax, cotton, and bean crops, and other crops of a similarnature. Although defoliation results in the killing of leaves, it is nota herbicidal action per se since the remainder of the plant is unharmed.Indeed, killing of the treated plant is undesirable when defoliation issought, since leaves will continue to adhere to a dead plant.

Another response demonstrated by plant growth regulants is the generalretardation of vegetative growth. This response has a wide variety ofbeneficial features. In certain plants it causes a diminution orelimination of the normal apical dominance, and thus leads to a shortermain stem and increased lateral branching. This alteration of thenatural growth or development produces smaller, bushier plants whichoften demonstrate increased resistance to drought and pest infestation.The retardation of vegetative growth in turf grasses is particularlydesirable. When the vertical growth rate of such grasses is lessened,root development is enhanced and a denser, sturdier turf is produced.The retardation of turf grasses also serves to increase the intervalbetween mowings of lawns, golf courses and similar grassy areas.

In many types of plants, such as silage crops, potatoes, sugar cane,beets, grapes, melons and fruit trees, the retardation of vegetativegrowth results in an increase in the carbohydrate content of the plantsat harvest. It is believed that the retardation or suppression of suchgrowth at the appropriate stage of development causes less of theavailable carbohydrate to be consumed for vegetative growth and resultsin an enhanced starch and/or sucrose content. Retardation of vegetativegrowth in fruit trees is demonstrated by shorter branches and greaterfullness of shape, and often results in lesser vertical elongation.These factors contribute to the ease of access to the orchard andsimplify the fruit harvesting procedure.

BRIEF DESCRIPTION OF THE INVENTION

It has now been discovered that novel trialkylsulfonium salts ofN-phosphonomethylglycine are useful in both regulating the naturalgrowth or development of plants and in controlling undesirablevegetation. These salts have the formula ##STR2## where R represents C₁-C₃ alkyl, and n is zero or one.

This invention further relates to a method of regulating the naturalgrowth or development of plants comprising applying to said plants aneffective, plant-regulating, non-lethal amount of the above compounds,as well as a method of controlling undesirable vegetation comprisingapplying a herbicidally effective amount of the compounds to suchvegetation when the latter is in a postemergence state.

As employed herein, the term "natural growth or development" designatesthe normal life cycle of a plant in accordance with its genetics andenvironment, in the absence of artificial external influences. Apreferred utility of the instant compounds is in increasing the sucroseyield of field grown sugarcane and sorghum. The term "regulating" isused herein to denote the bringing about through chemical means of anytemporary or permanent modification or variation from the normal lifecycle short of killing the plant.

The term "herbicidally effective amount" designates any amount of thecompounds disclosed herein which will kill a plant or any portionthereof. By "plants" is meant germinant seeds, emerging seedlings, andestablished vegetation, including roots and above-ground portions.Herbicidal effects include killing, defoliation, desiccation, stunting,leaf burn, and dwarfing. Herbicidal effects are generally achieved athigher application rates than growth regulating effects.

The term "alkyl" is used herein to include both straight-chain andbranched-chain alkyl groups. The carbon atom range is intended to beinclusive of its upper and lower limits.

Examples of specific compounds falling within the above formula are:

trimethylsulfonium salt of glyphosate

trimethylsulfoxonium salt of glyphosate

triethylsulfonium salt of glyphosate

triethylsulfoxonium salt of glyphosate

tripropylsulfonium salt of glyphosate

tripropylsulfoxonium salt of glyphosate

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the instant invention, regulation of the naturalgrowth or development of plants is achieved by the direct application ofa compound within the above formula or a formulation of such a compoundto the plants or to any of their above-ground portions at approximately4 to 10 weeks prior to harvest. With properly controlled application, agrowth regulating effect can be achieved without herbicidal results. Theamount which constitutes an effective amount varies not only with theparticular material selected for treatment, but also with the regulatoryeffect to be achieved, the species of plant being treated and its stageof development, and whether a permanent or transient effect is sought.Other factors which bear upon the determination of an appropriate plantregulating amount include the manner of application and weatherconditions such as temperature or rainfall. Growth regulation may arisefrom the effect of the compound on either the physiological processes orthe morphology of the plant, or from both in combination or in sequence.Morphological changes are generally noticeable by observable changes inthe size, shape, color or texture of the treated plant or any of itsparts, as well as in the quantity of fruit or flowers produced.

Changes in physiological processes, on the other hand, occur within thetreated plant and are usually hidden from the eye of an observer.Changes of this type most often occur in the production, location,storage or use of chemicals naturally occurring in the plant, such ashormones. Physiological changes may be visually detectable when followedby a change in morphology. In addition, numerous analytical proceduresfor determining the nature and magnitude of changes in the variousphysiological processes are known to those skilled in the art.

The compounds of the instant invention serve to regulate the naturalgrowth or development of treated plants in a number of diverse ways, andit is to be understood that each compound may not produce identicalregulatory effects on each plant species or at every rate ofapplication. As stated above, responses will vary in accordance with thecompound, the rate, the plant, etc.

Herbicidal effects are achieved in a similar manner, and the strength ofthe application can be varied to achieve the desired result.

The compounds of this invention are readily prepared fromN-phosphonomethylglycine by reacting the latter with silver oxide toform the silver salt or with sodium hydroxide to form the sodium salt,and treating either the silver or sodium salt with a trialkylsulfoniumor -sulfoxonium halide. Alternatively, the glycine can be reacteddirectly with the trialkylsulfonium or -sulfoxonium halide in thepresence of propylene oxide. N-Phosphonomethylglycine is a commerciallyavailable material known by the common name "glyphosate." It can beprepared by the phosphonomethylation of glycine, the reaction of ethylglycinate with formaldehyde and diethylphosphite, or the oxidation ofthe N-phosphinomethylglycine. Such methods are described in U.S. Pat.No. 3,799,758 (Franz, Mar. 26, 1974).

As illustrated in the examples which follow, the compounds of theinvention can either regulate the natural growth or development ofplants or kill weeds. While regulatory responses are often desirable intheir own right, their effect on crop economics is most often of primarysignificance. Thus, increases in the yield of individual plants,increases in the yield per unit area, and reductions in the cost ofharvesting and/or subsequent processing are all to be considered inassessing the consequence of an individual regulatory effect during thegrowth or development of a plant.

The specific examples which follow are presented as merely illustrative,non-limiting demonstrations of the preparation of the compounds of theinstant invention and of their effectiveness in regulating the growth ofplants and in controlling undesirable vegetation.

EXAMPLE 1 Mono-Trimethylsulfonium Salt of Glyphosate

A solution was prepared consisting of 80 ml of tetrahydrofuran and 20 mlof water. To this solution was added 1.7 g (0.01 mole) ofN-phosphonomethylglycine, obtained from Monsanto Agricultural Products,Co., St. Louis, Mo., and 0.4 g (0.01 mole) of powdered sodium hydroxide.Then 2.0 g (0.01 mole) of trimethylsulfonyl iodide was added and a clearsolution resulted. The solution was then stripped of volatiles,dispersed in ethanol, and heated to 60° C. Filtration and dryingproduced 1.8 g of a white powder, whose molecular structure wasconfirmed by carbon-13 and proton nuclear magnetic resonance as that ofthe mono-trimethylsulfonium salt of N-phosphonomethylglycine.

EXAMPLE 2 Mono-Trimethylsulfoxonium Salt of Glyphosate

A reaction vessel was charged with 50 ml of water, 4.2 g (0.025 mole) ofN-phosphonomethylglycine, and 5.5 g (0.025 mole) of trimethylsulfoxonyliodide. The vessel was heated gently in a water bath and 15 ml ofpropylene oxide was added. The mixture was stirred for one hour thenwashed with ether and phase separated. The aqueous phase was thenstripped, yielding 5.8 g of a white powder with a melting point range of184°-186° C. The molecular structure of the product was confirmed bycarbon-13 and proton nuclear magnetic resonance as that of themono-trimethylsulfoxonium salt of N-phosphonomethylglycine.

Other compounds within the scope of the generic formula shown above canbe prepared by either of these methods with appropriate startingmaterials.

EXAMPLE 3

This example illustrates the utility of the compound prepared in Example1 in regulating the growth of sweet sorghum (scientific name: Sorghumvulgare).

The following test procedure was used:

A series of white plastic pots, 7.5 inches (19.0 cm) in diameter, werefilled with approximately 10 pounds (4.54 kilograms) each of sandy loamsoil containing 100 parts per million (ppm) ofcis-N[(trichloromethyl)thio]-4-cyclohexene-1,2-dicarboximide (acommercially available fungicide) and 150 ppm of 17-17-17 fertilizer(i.e., comprising 17% by weight each of N, P₂ O₅, and K₂ O). Eightsorghum seeds were placed in each pot and the pots were placed in agreenhouse in which the temperature was maintained at 27° C. during theday and 21° C. at night. During the next five weeks, the emerging plantswere thinned down to one per pot. The pots were fertilized periodicallywith 17-17-17 fertilizer.

The plants were sprayed 114 days after seeding with a solutionconsisting of the test compound dissolved in equal portions of acetoneand water. The spraying system was pressurized by carbon dioxide andmounted on a bicycle-type apparatus. The test solution was sprayed at arate of 80 gallons per acre (750 liters per hectare). The concentrationof the solution was pre-determined to produce the desired applicationrate in pounds per acre (lb/A) when sprayed on the plants at a totalvolume of 80 gallons per acre. The concentration was thus selected tocorrespond to an application rate of 0.25 lb/A (0.28 kilograms perhectare).

Following treatment, the plants were placed in the greenhouse for anadditional 39 days. During this time, the degree of seedhead emergenceand pollen shedding were recorded periodically. The plants were thenharvested. The stalks were cut at soil level and the seedhead andpeduncle were removed. For each stalk, the seedhead was dried and thenweighed, and the peduncle length was measured. The remainder of thestalk was then stripped of all leaves and leaf sheaths, and its lengthand weight were determined. The stalks were then chopped into smallsegments and squeezed in a hydraulic press at a pressure of 20,000pounds per square inch (13,800 Newtons per square centimeter). Thequantity of the expressed juice was measured as well as its quality interms of total dissolved solids. The latter was measured with a handjuice refractometer, and is expressed as weight percent of the juice.

Five replications were performed at each application rate. In addition,five untreated plants were included as check plants for comparison. Theresults are shown in Tables I and II.

Table I lists the data pertaining to seedhead emergence and pollenshedding. The data listed are averages of each set of five replications.It is clear in each case that both the extent of seedhead emergence andpollen shedding were reduced when the test solutions were applied. Thisreduction in flowering is one indication of an increase in theefficiency of sucrose production and storage.

Table II lists averages of the measurements taken on the seedhead,peduncle, stalk, and expressed juice after the harvesting of the plants.The data indicate a reduction in the dried seedhead weight, the pedunclelengths, and the height and weight of the stalk, as compared to thecheck plant averages.

                  TABLE I                                                         ______________________________________                                        PRE-HARVEST DATA                                                              Averages of 5 Replications Each                                                ##STR3##                                                                     Seedhead Emergence (%) and Pollen Shedding (%)                                       DAYS AFTER SEEDING:                                                    Application                                                                            121      131      135    138    149                                  Rate (lb/A)                                                                            SE    PS     SE  PS   SE  PS   SE  PS   SE  PS                       ______________________________________                                        0 (check)                                                                              0     0      20  7    42  33   74  55   93  93                       0.25     0     0       0  0     0   0    0   0    0   0                       ______________________________________                                    

                  TABLE II                                                        ______________________________________                                        POST-HARVEST DATA                                                             Averages of 5 Replications Each                                                ##STR4##                                                                     Appli- Dried    Pe-                                                           cation Seedhead duncle  Stalk     Expressed Juice                             Rate   Weight   Length  Height                                                                              Weight                                                                              Amount TDS*                               (lb/A) (g)      (mm)    (mm)  (g)   (g)    (wt %)                             ______________________________________                                        0 (check)                                                                            10.2     234     711   94.5  18.0   13.5                               0.25   0.5      20      490   90.2  15.6   13.4                               ______________________________________                                         *TDS: Total Dissolved Solids                                             

This example demonstrates the postemergence herbicidal activity of thecompounds prepared in Examples 1 and 2.

Aluminum planting flats measuring 15.2×22.9×8.9 cm were filled to adepth of 7.6 cm with loamy sand soil, containing 50 parts per million(ppm) each of the commercial fungicidecis-N[(trichloromethyl)thio]-4-cyclohexene-1,2-dicarboximide (Captan®)and 17-17-17 fertilizer (percentages of N-P₂ O₅ -K₂ O) on a weightbasis). Several rows were impressed across the width of each flat and avariety of seeds of both grass and broadleaf weed species were planted,one species per row. The weed species used are listed below:

    ______________________________________                                        Broadleaf weeds:                                                              A. Annual mornining glory                                                                         Ipomoea purpurea                                          B. Cocklebur        Xanthium sp.                                              C. Jimsonweed       Datura stramonium                                         D. Velvetleaf       Abutilon theophrasti                                      E. Mustard          Brassica sp.                                              F. Nightshade       Solanum sp.                                               G. Pigweed          Amaranthus sp.                                            Grasses:                                                                      H. Yellow nutsedge  Cyperus esculentus                                        I. Downybrome       Bromus tectorum                                           J. Foxtail          Setaria sp.                                               K. Annual ryegrass  Lolium multiflorum                                        L. Watergrass       Echinochloa crusgalli                                     M. Shattercane      Sorghum bicolor                                           N. Wild oat         Avena fatua                                               ______________________________________                                    

The broad leaf species were seeded first, and the grasses were seededfour days later. Ample seeds of each species were planted to produce 20to 50 seedlings per row after emergence, depending on the size of eachplant.

Ten days after the grasses were seeded, the emerged seedlings of allspecies were sprayed with aqueous solutions of the test compounds. Thesolutions were prepared to such dilutions that a spray rate of 80gallons per acre (750 liters per hectare) gave from 0.5 to 4.0 pounds oftest compound per acre (0.56 to 4.48 kilograms per hectare) as desiredfor each test. Additional flats not treated at all were used asstandards for measuring the extent of weed control in the treated flats.

Nineteen days later, the test flats were compared to the standards andthe weeds in each row were rated visually in terms of percent controlranging from 0% to 100%, with 0% representing the same degree of growthas the same row in the standard and 100% representing complete kill ofall weeds in the row. All types of plant injury were taken intoconsideration. The results are shown in Table III.

                                      TABLE III                                   __________________________________________________________________________    HERBICIDAL TEST RESULTS                                                                            Percent Control                                                       Application                                                                           Broadleaf Weeds      Grasses                             Test Compound                                                                              Rate (lb/A)                                                                           A  B  C  D  E  F  G  H  I  J  K  L  M  N                 __________________________________________________________________________    N--phosphonomethyl-                                                                        0.5     50  50                                                                               60                                                                              65  65                                                                              75 50 75 40  95                                                                               98                                                                               65                                                                               60                                                                              35                glycine, trimethyl-                                                                        1.0     65  70                                                                               70                                                                              70  80                                                                              80 70 80 60 100                                                                              100                                                                               80                                                                               95                                                                              50                sulfonium salt                                                                             2.0     70 100                                                                               85                                                                              90 100                                                                              85 80 80 70 100                                                                              100                                                                               90                                                                              100                                                                              65                             3.0     80 100                                                                              100                                                                              100                                                                              100                                                                              95 100                                                                              90 75 100                                                                              100                                                                              100                                                                              100                                                                              90                             4.0     95 100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              90 100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100               N--phosphonomethyl-                                                                        0.5     45  40                                                                               60                                                                              65  65                                                                              60 60 65 70  95                                                                               95                                                                               90                                                                               90                                                                              70                glycine, trimethyl-                                                                        1.0     80  70                                                                              100                                                                              85  95                                                                              90 80 80 80 100                                                                              100                                                                              100                                                                              100                                                                              85                sulfoxonium salt                                                                           2.0     90 100                                                                              100                                                                              95 100                                                                              100                                                                              100                                                                              80 90 100                                                                              100                                                                              100                                                                              100                                                                              90                             3.0     95 100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              85 100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                            4.0     100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              90 100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100               __________________________________________________________________________

EXAMPLE 5 Mono-Triethylsulfonium Salt of Glyphosate

A reaction vessel was charged with 100 ml of water, 4.2 g (0.025 mole)of N-phosphonomethylglycine, and 6.2 g (0.025 mole) of triethylsulfoniumiodide. The reaction mixture was heated to 50° C. and stirred at thistemperature for one hour. It was then cooled to 15° C. and 15 ml ofpropylene oxide was added. The resulting mixture was stirred at roomtemperature for two hours, then washed with ether and phase separated.The aqueous phase was then stripped, redissolved in ethanol, dried withsodium sulfate and washed again with ether. The final yield was 7.5 g ofa liquid with a refractive index of n_(D) ³⁰ =1.5197. The molecularstructure of the product was confirmed by carbon-13 nuclear magneticresonance and infrared spectroscopy as that of themono-triethylsulfonium salt of N-phosphonomethylglycine.

EXAMPLE 6

This example demonstrates the postemergence herbicidal activity of thecompound prepared in Example 5. The procedure described in Example 4 wasused, with the following modifications: the species pigweed was notincluded; the grass species were seeded three days after the broadleafspecies; treatment of the emerged seedlings with the test compound wasdone eleven days after the grasses were seeded; and injury ratings weretaken twenty-one days after treatment. The results are shown in TableIV.

                                      TABLE IV                                    __________________________________________________________________________    HERBICIDAL TEST RESULTS                                                       Test Compound:                                                                N--phosphonomethylglycine,                                                    triethylsulfonium salt                                                               Percent Control                                                        Application                                                                          Broadleaf Weeds   Grasses                                              Rate (lb/A)                                                                          A  B  C  D  E  F  H  I  J  K  L  M  N                                  __________________________________________________________________________    0.25   45 50 35 40 65 60 25  45                                                                              100                                                                               80                                                                               75                                                                               50                                                                              45                                 0.5    55 65 40 55 80 90 60  80                                                                              100                                                                               90                                                                               95                                                                              100                                                                              75                                 1.0    80 80 55 65 85 95 75 100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              90                                 2.0    85 100                                                                              65 90 90 100                                                                              85 100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              95                                 3.0    100                                                                              100                                                                              90 100                                                                              100                                                                              100                                                                              95 100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                __________________________________________________________________________

METHODS OF APPLICATION

Whether used as plant growth regulators or as herbicides, the compoundsof the present invention are most useful when applied directly to theplants subsequent to their emergence from the soil. In use at anagricultural field site, the compounds are generally embodied insuitable formulations containing additional ingredients and diluentcarriers to aid in their dispersal. Examples of such ingredients orcarriers are water, organic solvents, dusts, granules, surface activeagents, water-in-oil and oil-in-water emulsions, wetting agents,dispersing agents, and emulsifiers. The formulations generally take theform of dusts, solutions, emulsifiable concentrates, or wettablepowders.

A. DUSTS

Dusts are dense powder compositions which combine the active compoundswith a dense, free-flowing solid carrier. They are intended forapplication in dry form and are designed to settle rapidly to avoidbeing windborne to areas where their presence is not desired.

The carrier may be of mineral or vegetable origin, and is preferably anorganic or inorganic powder of high bulk density, low surface area, andlow liquid absorptivity. Suitable carriers include micaceous talcs,pyrophyllite, dense kaolin clays, tobacco dust, and ground calciumphosphate rock.

The performance of a dust is sometimes aided by the inclusion of aliquid or solid wetting agent, of ionic, anionic, or nonionic character.Preferred wetting agents include alkylbenzene and alkylnaphthalenesulfonates, sulfated fatty alcohols, amines or acid amides, long chainacid esters of sodium isothionate, esters of sodium sulfosuccinate,sulfated or sulfonated fatty acid esters, petroleum sulfonates,sulfonated vegetable oils, and ditertiary acetylenic glycols.Dispersants are also useful in the same dust compositions. Typicaldispersants include methyl cellulose, polyvinyl alcohol, ligninsulfonates, polymeric alkylnaphthalene sulfonates, sodium naphthalenesulfonate, polymethylene bisnaphthalenesulfonate, andsodium-N-methyl-N-(long chain acid) taurates.

In addition, inert absorptive grinding aids are frequently included indust compositions to aid in the manufacturing of the dust. Suitablegrinding aids include attapulgite clay, diatomaceous silica, syntheticfine silica and synthetic calcium and magnesium silicates.

In typical dust compositions, carriers are usually present inconcentrations of from about 30 to 90 weight percent of the totalcomposition. The grinding aid usually constitutes about 5 to 50 weightpercent, and the wetting agent up to about 1.0 weight percent.Dispersants, when present, constitute up to about 0.5 weight percent,and minor amounts of anticaking and antistatic agents may also bepresent. The particle size of the entire composition is usually about 30to 50 microns.

B. SOLUTIONS

Aqueous solutions of the active compounds are prepared such thatapplication at the rate of about 1 to about 200 gallons of solution peracre (about 9 to about 1875 liters per hectare) will provide therequired amount of active ingredient. A small amount of non-phytotoxicsurfactant typically between 0.05% and 0.5% by weight is usuallyincluded to improve the wetting ability of the solution and thus itsdistribution over the plant surface. Anionic, cationic, nonionic,ampholytic, and zwitterionic surfactants are all useful in this regard.

Suitable anionic surfactants include alkali metal, ammonium, and aminesalts of fatty alcohol sulfates having from 8-18 carbon atoms in thefatty chain and sodium salts of alkyl benzene sulfonates having from 9to 15 carbon atoms in the alkyl chain. Suitable cationic surfactantsinclude dimethyl dialkyl quaternary ammonium halides with alkyl chainsof 8 to 18 carbon atoms. Suitable nonionic surfactants includepolyoxyethylene adducts of fatty alcohols having 10 to 18 carbon atoms,polyethylene oxide condensates of alkyl phenols with alkyl chains of 6to 12 carbon atoms and 5 to 25 moles of ethylene oxide condensed ontoeach mole of alkyl phenol, and polyethylene oxide condensates ofsorbitan esters with 10 to 40 moles of ethylene oxide condensed ontoeach mole of sorbitan ester. Suitable ampholytic surfactants includesecondary and tertiary aliphatic amine derivatives with one aliphaticsubstituent containing 8 to 18 carbon atoms and another containing ananionic water-solubilizing group such as a sulfate or sulfonate.Sodium-3-dodecylaminopropionate and sodium-3-dodecyl amino propanesulfonate are examples. Suitable zwitterionic surfactants includederivatives of aliphatic quaternary ammonium compounds with onealiphatic substituent containing 8 to 18 carbon atoms and anothercontaining an anionic water-solubilizing group. Examples of are3-(N,N-dimethyl-N-hexadecylammonio)propane-1-sulfonate and3-(N,N-dimethyl-N-hexadecylammonio)-2-hydroxy propane-1-sulfonate.

C. EMULSIFIABLE CONCENTRATES

Emulsifiable concentrates are solutions in which the active materialsand an emulsifying agent are dissolved in a non-watermiscible solvent.Prior to use, the concentrate is diluted with water to form a suspendedemulsion of solvent droplets.

Typical solvents for use in emulsifiable concentrates include weed oils,chlorinated hydrocarbons, and non-water-miscible ethers, esters, andketones.

Typical emulsifying agents are anionic or nonionic surfactants, ormixtures of the two. Examples include long-chain mercaptan polyethoxyalcohols, alkylaryl polyethoxy alcohols, sorbitan fatty acid esters,polyoxyethylene ethers with sorbitan fatty acid esters, polyoxyethyleneglycol esters with fatty or rosin acids, fatty alkylol amidecondensates, calcium and amine salts of fatty alcohol sulfates,oil-soluble petroleum sulfonates, or preferably mixtures of theseemulsifying agents. Such emulsifying agents usually comprise about 1 to10 weight percent of the total composition.

Typical emulsifiable concentrates contain about 15 to 50 weight percentactive material, about 40 to 82 weight percent solvent, and about 1 to10 weight percent emulsifier. Other additives such as spreading agentsand stickers can also be included.

D. WETTABLE POWDERS

Wettable powders are water-dispersible compositions containing theactive material, an inert solid extender, and one or more surfactants toprovide rapid wetting and prevent flocculation when suspended in water.

Suitable solid extenders include both natural minerals and materialsderived synthetically from such minerals. Examples include kaolinites,attapulgite clay, montmorillonite clays, synthetic silicas, syntheticmagnesium silicate and calcium sulfate dihydrate.

Suitable surfactants include both nonionic and anionic types, andfunction as wetting agents and dispersants. Usually one of each isincluded. Preferred wetting agents are alkylbenzene and alkylnaphthalenesulfonates, sulfated fatty alcohols, amines or acid amides, long chainacid esters of sodium isothionate, esters of sodium sulfosuccinate,sulfated or sulfonated fatty acid esters, petroleum sulfonates,sulfonated vegetable oils, and ditertiary acetylenic glycols. Preferreddispersants are methyl cellulose, polyvinyl alcohol, lignin sulfonates,polymeric alkylnaphthalene sulfonates, sodium naphthalene sulfonate,polymethylene bisnaphthalenesulfonate, and sodium-N-methyl-N(long chainacid) taurates.

Typical wettable powders contain 25 to 90 percent active material, 0.5to 2.0 percent wetting agent, 0.25 to 5.0 percent dispersant, and from9.25 to 74.25 weight percent inert extender. Frequently, 0.1 to 1.0percent of the extender is replaced by a corrosion inhibitor and/or anantifoaming agent.

E. IN GENERAL

In general, any conventional postemergence method of application can beused, including common dusting or spraying equipment. The amount ofactive ingredient which is effective in producing the desired result, beit herbicidal or growth-regulating, depends on the nature of the plantspecies to be controlled and the prevailing conditions. Herbicidaleffects are usually achieved at 0.1 to 50 pounds active ingredient peracre, preferably 1 to 10, while plant growth regulation is usuallyachieved at 0.1 to 20 pounds active ingredient per acre, preferably 0.5to 5. It will be readily apparent to one skilled in the art thatcompounds of lower activity will require a higher dosage than moreactive compounds for the same degree of control.

What is claimed is:
 1. A compound having the formula ##STR5## in which nis zero or one.
 2. A compound according to claim 1 in which n is zero.3. An herbicidal composition comprising an herbicidally effective amountof a compound having the formula ##STR6## in which n is zero or one, andan inert diluent carrier.
 4. A composition according to claim 3 in whichn is zero.
 5. A method of controlling undesirable vegetation comprisingapplying to the vegetation in postemergent state an herbicidalcomposition comprising an herbicidally effective amount of a compoundhaving the formula ##STR7## in which n is zero or one, and an inertdiluent carrier.
 6. A method according to claim 5 in which n is zero.